Europhys. Lett.
Volume 65, Number 1, January 2004
Page(s) 116 - 122
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 December 2003
Europhys. Lett., 65 (1) , pp. 116-122 (2004)
DOI: 10.1209/epl/i2003-10059-5

Giant Keplerate molecule $\chem{Fe_{30}}$ -the first octopole magnet

A. S. Mischenko1, A. S. Chernyshov1 and A. K. Zvezdin2

1  Physics Department, Moscow Lomonosov State University - 119889 Moscow, Russia
2  General Physics Institute of RAS - 119991 Moscow, Russia

(Received 8 July 2003; accepted in final form 30 October 2003)

The multipole expansion technique is applied to one of the largest magnetic molecules, $\chem{Fe_{30}}$. The molecule's dipole, toroid and quadrupole magnetic moments are equal to zero (in the absence of magnetic field) so the multipole expansion starts from the octopole moment. Probably, the $\chem{Fe_{30}}$ molecule is the most symmetrical magnetic body synthesized so far. The magnetization process is considered theoretically in different geometries. Some components of the octopole moment experience a jump while the magnetization rises linearly up to its saturation value. An elementary octopole moment consisting of four magnetic dipoles is proposed as a hint for designing of an experiment for the measurement of octopole magnetic-moment components.

75.50.Xx - Molecular magnets.
75.10.Hk - Classical spin models.

© EDP Sciences 2004